That is a stinging re-affirmation of why factory ammunition should be individually inspected before loading into the magazine. And people say they don't trust handloads! Sorry, both are produced by humans, and both can contain defects. I have suffered more factory ammo defects over the years than I have defects from my handloads, and numbers wise, that is a terrible thing to say about factory ammunition.
It probably would have worked just fine, though. I doubt that you would have noticed anything different if you had fired it, if you did not get to see the ejected case.
Eddie Rickenbacker used to inspect each and every cartridge before he went on a flight. Not a bad idea for any of us, nearly a century later.